Equation Strips

In Ontario our grade 7 students are introduced to solving simple equations in the form ax + b = c where the values of a, b and c are whole numbers. We think it's a good idea for them to start by having some sort of visual representation of each equation. In this activity, students are given 16 cards that correspond to 16 equations represented as strips (the top and bottom of the strips represent the left and right sides of the equations). They are more commonly called bar models but we have always used the name equation strips. Students solve for x given the strips and then rewrite the algebraic form equation. We originally got this idea from the 2011 Solving Equations Gap Closing resource (pg14).
[Updated Mar 6, 2018 - now both the printable cards and the dynamic websketch have equations in the form 2x - 5 = 19. This puts it beyond the grade 7 expectation but could be an extension or just used for grade 8]
[Updated Dec 19, 2019 - now including a single dynamic Desmos version where you can switch all the versions using sliders as well as a Desmos Activity where students first do some static practice problems and then it finishes with a Challenge Creator where students make their own question for the others to solve]

[Updated May 9th, 2022 - I added a card sort to the Desmos Activity and included a pdf version]

• Grade 7 Patterning & Algebra - solve linear equations of the form ax = c or c = ax and ax + b = c or variations such as b + ax = c and c = bx + a (where a, b, and c are natural numbers) by modelling with concrete materials, by inspection, or by guess and check, with and without the aid of a calculator 
• Grade 8 Patterning & Algebra - as review

• Each group gets a set of 16 cards (24 if you use the cards with minuses)
• Make several copies of the cards on card stock and laminate them so they last longer. You may wish to copy each set onto a different colour so that if they get mixed up you know each set by their colour.
• Cut out the cards so that each group gets a set of 16. 

1. Each group of 2-3 students gets one full set of 16 cards. 
2. Students are to determine the value of x for each card.
3. Once determining x then they should then determine the algebraic expression for each card
4. You can circulate with the solution card to check answers.
5. Once finished you can create your own cards using this web sketch or this Desmos sketch. This allows you to change the coefficients of a, b & c and it generates all four possible configurations. This web sketch assumes that a, b & c will be whole numbers and will not allow any solutions that have x as negative. Once you put your coefficients in then take a screenshot, use the screen capture software of your choice to copy and paste the version you want to use (For Windows use the Snipping Tool, for Chromebooks use Shift CTRL F5, for Macs use Command Shift 4, or iPad use the Home and Sleep buttons together. You can then paste into the word processor of your choice. 
6. If using the Desmos Activity, pair students so that they can have conversations about the
   
   strips. Be sure to explain how when they create their challenge, they will first have to solve it before they can submit it for the rest of the class to do. When using the Desmos activity, note that the "x's" are missing to make the connections to explicit equations less visible. This is so that students are free from the stigma of actual equations while still solving them. You might want to start with this. 

Note that if you want to modify the Desmos activity, you might want to watch this video on how to do it:

[Added July 2024] And here is @Howie_Hua doing some explainer videos of how to use Equation Strips (Bar Models)

Introducing one-step and two-step linear equations with bar models (Part 1) pic.twitter.com/eGlrAe0FNX

— Howie Hua (@howie_hua) July 18, 2024

(Part 2) pic.twitter.com/pyxqew4G7h

— Howie Hua (@howie_hua) July 18, 2024

• Equation Strip Cards Print version (Google Doc, PDF)
• Equation Strip Solution card (Google Doc, PDF)
• Equation Strip Card Sort (Google Doc, PDF)
• Equation Strip Solution template
• Equation Strip Web Sketch
• Desmos Sketch
• Desmos Activity

Did you use this activity? Do you have a way to make it better? If so tell us in the comment section. Thanks 

Number Sentences Sort (update)

One of the smaller expectations we have to deal with is the ability for students to interpret algebraic equations. You know: "what does 2x + 1 mean"?. We created this very simple sorting activity where students are given expressions (and equations) and the sentence to describe them and have to match them up. This is meant to be an activity that is relatively quick. We have two versions here. One for grade 7 that only has expressions and one for grade 8 that has equations as well. We also have an Explain Everything version of each so that if you have an iPad (or Chromebook), with that app, you can have your students sort them electronically. This can also be used as review in Grade 9.
Note: This is an update to the same activity posted last year but now with a grade 8 and Explain Everything version
Double Note: This has been updated again to now include a Desmos card sort. So both card sorts are now transferred to this new Desmos feature. You can learn about Desmos Card Sorts by clicking here. Download the Teacher versions (which you can copy) of these activities below in the download section.

• Gr7PA - translate phrases describing simple mathematical relationships into algebraic expressions using concrete materials
• Gr8PA - translate statements describing mathematical relationships into algebraic expressions and equations
• MPM1D, MFM1P - As review

• For the grade 7 version there are four different (but similar) sets. One set per page. For the grade 8 version there are three different (but similar) sets. One set per page. 
• Print each page on card stock (we also suggest laminating). We suggest that each set be printed on different colour card stock for easy sorting. Cut each out and put each set in an envelope.
• Obviously you will have to decide how many sets you will need for your class depending on whether you pair students up or not. 
• Note that in the version with equations, there are some algebraic expressions that do not have matching sentences. In these cases, students will have to write their own.
• If you choose to use the Explain Everything version, then you probably want to download that .xpl file and put it on a server where your students can get easy access to it. 

Explain Everything Screenshot

1. Depending on how many students you have you may want to do this individually, in pairs or in larger groups. The activity is not super complex so we don't recommend anything bigger than pairs. 
2. Students take each set and sort the algebraic expression with the written version. 
3. When they are done their set they can trade with another group that has a different colour of cards. If they are using the Explain Everything version then they can just go to the next slide. 
4. There is a homework sheet for consolidation that includes both expressions and equations as well.

• NumberSentences-Expressions (doc. PDF, XPL, Desmos)
• NumberSentences-Equations (doc, PDF, XPL, Desmos)
• NumberSentencesHomework-Equations (doc, PDF)
• Entire Folder

Did you use this activity? Do you have a way to make it better? If so tell us in the comment section. Thanks

Gr 8 Algebra and EquationsTower Challenge

This is a review activity on algebra and solving simple linear equations for grade 8 where students answer questions and are rewarded with building materials for each correct answer. The building materials (straws & tape) are then used to create the tallest tower that can hold a cup with a ball.  In this activity students have a different tower challenge than our 9 academic and 9 applied versions.  

Gr8 Patterning and Algebra

• translate statements describing mathematical relationships into algebraic expressions and equations
• evaluate algebraic expressions with up to three terms, by substituting fractions, decimals, and integers for the variables
• solve and verify linear equations involving a one-variable term and having solutions that are integers, by using inspection, guess and check, and a “balance” model
• make connections between solving equations and determining the term number in a pattern, using the general term
• describe different ways in which algebra can be used in real-life situations

• 1-2 boxes of straws and 1-inch pieces of tape
• a small container with ping pong ball 
• a question sheet for each student
• a teacher answer sheet 
• Optional - a whiteboard for each student to work out their solutions
• Optional - prize for the group with the tallest tower that can hold the cup

1. Place students in groups (ideally no bigger than 3 per group)
2. Hand out question sheets (and optional whiteboards) to each student.
3. Have students answer questions from their sheet in any order they want. For every correct answer they will get some building materials (eg: 2 straws & 2 pieces of tape, the amount of each reward is indicated on the student question sheet ). The harder the question the more materials they will get. Eventually the building materials will be used to create the tallest free standing tower that can hold the cup with ball.
4. Students work in groups to answer the questions and bring their solutions up to you to be checked. Only one member from each group can come up at a time. Each group can answer each question only once. To keep track of this, use the teacher answer sheet to check off which questions each group has answered as they come up.
5. Leave about 20 min at the end of the class for students to create their towers (students can no longer answer questions)
6. Take lots of pictures and celebrate the group with the tallest free standing tower.

The video, below, is only visible in the WECDSB domain. That is, only teachers in our school board can see the video if they are logged into their MyTools2Go accounts.

• Gr8AlgebraTowerChallengeQuestions (pdf, doc)
• Gr8AlgebraTowerChallengeTeacherAnswerSheet (pdf, doc)

Did you use this activity? Do you have a way to make it better? If so tell us in the comment section. Thanks

Linear Scavenger Hunt

The linear scavenger hunt is an activity where there are sets of four representations of linear relations on cards (graphical, tabular, algebraic and word problem) that students have to search for and match.

• MPM1D, MFM1P, MFM2P
• determine values of a linear relation by using a table of values, by using the equation of the relation, and by interpolating or extrapolating from the graph of the relation
• determine other representations of a linear relation, given one representation
• describe the meaning of the slope and y-intercept for a linear relation arising from a realistic situation 
• determine the equation of a line from information about the line

• Linear Scavenger Hunt Cards (printed 1 sided)
• Linear Scavenger Hunt Question Cards (printed back to back)
• Tape/stick tack
• Beach Ball (optional)
• Whiteboard markers (optional)

1. Each group of 3 students gets 1 representation of a linear relationship  - either a story, equation, table or graph.  Students will complete a scavenger hunt by roaming around the room to find the other 3 representations of their linear relationship. The other three cards in each set are randomly distributed around the class before hand.
2. Once all four cards are together, each group must fill in missing information on the graph (title and axes labels) and in the table (column titles and table values -  CAUTION:  yellow rows are out of step in the pattern). Teacher can check missing information quickly using reference card.
3. Each group will tape their equation in the middle of their desks.
4. Each group will now tape their story to the beach ball.  Students will throw the ball and each group will select a card (not their own).  That group must now find the equation of the new story they got off the beach ball.  One member will then circulate to check if the equation is correct with the original group for their new story and return it to that group.
5. Repeat step 4 with the tables.
6. Repeat step 4 with the graphs.
7. Each group should now have the original 4 representations of their linear relationship.  Students will now answer 5 questions related to their relationship found on the Question Cards.  

Other possible uses

• give a story or equation to each student and have them find their partner
• give each group of 3 an equation and have them describe several situations that could be modelled by the given linear equation.
• give students a card and have them identify as a direct or partial variation
• give a student a table or graph - have them find the rate and explain its meaning

The video, below is only visible in the WECDSB domain. That is, only teachers in our school board can see the video if they are logged into their MyTools2Go accounts.

• Linear Scavenger Hunt Cards (doc) (pdf)
• Linear Scavenger Hunt Question Cards (doc) (pdf)
• Note that if you print these out on card stock and laminate them, students can use whiteboard markers or whiteboard crayons to do their work on them and can be reused.

Did you use this activity? Do you have a way to make it better? If so tell us in the comment section. Thanks